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The world's best gem articles, published weekly.

Most Recent Articles

Eight Opal Types Explained

Opal is a complicated gemstone, and many factors affect its price. Learn how to distinguish these eight opal types and how they differ in value.

Radiant-Cut Diamonds: Modern & Durable

Exceptionally sparkly, radiant-cut diamonds are great for engagement rings. But how can you find a top-quality gem? Read our tips for buying radiants here.

Diamond Girdles: 11 Facts You Need to Know

Buying a diamond but unsure about the girdle? Learn everything you need to know about diamond girdles, including thickness ratings and girdle inscriptions.

How Do Opals Form?

Curious about how opals form and show such stunning colors? Learn about the scientific theories behind opal formation and why some opals show a rainbow.

Two-Carat Diamond Rings: Buying Top Quality

A two-carat diamond engagement ring is sure to turn heads. Learn how to choose a top-quality diamond in this size while staying in your budget.

Whewellite Value, Price, and Jewelry Information

Seldom seen even in mineral collections, whewellite is very rarely faceted. It’s mostly desired as a curiosity because of its scarcity, chemical composition, and unusual — sometimes organic — origins.

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"Becoming a Pro Member of IGS just made good sense for my business. The gemology resources are fantastic, and my profile lets potential customers know I am serious about colored gemstones. And frankly, if I get any exposure to potential customers it's a no-brainer."
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Jeweler, IGS Pro Member

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Over 15 years, we have assembled detailed pricing and value information for appraising over 70 different gemstones. The values in our guide come from a variety of sources including primary and secondary gemstone dealers, jewelers, miners, and wholesale suppliers of commonly traded gemstones.

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